The present invention relates to apparatus for extracting charging gases through an orifice in the roof of one coke oven chamber and for discharging the gases to an adjacent, second coke oven chamber through openings in the roofs of the respective chambers. In the usual case, gases extracted from the first chamber are discharged into a second chamber which is separated from the first by an intermediate chamber.
More particularly, the invention relates to apparatus including a generally U-shaped pipe or conduit, disposed for vertical movement on a truck movable along the top of a coke oven battery, the pipe having downwardly-extending end portions each having an annular sealing end which dips into a water seal provided in a riser surrounding an opening in the roof of the coke oven chamber. The risers are normally closable by covers. While coking proceeds in one oven chamber, the suction applied by the gas-collecting main of the battery is adjusted to draw the charging gases through the conduit or pipe from the other coking chamber while it is being charged. In this manner, a large portion of the charging gases and dust evolved during charging of an oven chamber can be extracted and discharged into another chamber where coking is proceeding.
Apparatus of this type for extracting charging gases is shown, for example, in U.S. Pat. No. 4,314,889, issued Feb. 9, 1982. In the apparatus shown in that patent, gases are extracted from one coke oven chamber and discharged into another by initially removing the covers from the risers, whereupon the aforesaid conduit is lowered onto the openings in the furnace roof and into water seals provided in the risers so that a gas-tight closure is provided. If the suction from the nearby chamber is increased, some of the gases being evolved from the chamber being charged flow through the conduit. Upon completion of charging, the conduit is raised and the covers again secured to the risers.
In an operation of the type described above, explosions often occur when the conduit is lifted from the risers, the explosions occurring not only with water-sealed transfer conduits but also with transfer conduits having other forms of seals. The reason for the explosions is that when the conduit is lifted, residual gases combine with oxygen to form an explosive mixture which ignites at the high temperatures present.